EVIDENCE FOR FREE RADICAL-MEDIATED LIPID-PEROXIDATION AT REPERFUSION OF HUMAN ORTHOTOPIC LIVER-TRANSPLANTS

Background. Generation of toxic oxygen metabolites at reperfusion may contribute to the injury sustained as a consequence of harvest and isc hemic preservation of organ organ allografts. Because there is a pauci ty of evidence that this mechanism is operative in human beings, we me asured the generation of ethane into the exhaled breath as a biomarker of free radical-mediated lipid peroxidation in human liver transplant ation. Methods. A novel technique that increased the previous standard of sensitivity 100-fold was used to measure picomole quantities of et hane in exhaled breath of eight recipients undergoing human orthotopic liver transplantation. Results. Ethane production correlated closely with the specific events of liver transplantation including the initia l reperfusion of the allografts. In every case a twofold to threefold increase in ethane production was superimposed on a stable baseline im mediately after reestablishment of portal vein blood flow through the donor liver. Conclusions. Ethane production was interpreted as evidenc e of hepatic lipid peroxidation, presumably mediated by toxic metaboli tes of oxygen occurring at reperfusion. This noninvasive approach allo wed localization of the time point at which lipid peroxidation occurre d and may facilitate quantification of lipid peroxidation mediated by free radicals and other toxic oxygen metabolites during operation.